The basics of how a muscle generates power remain the same: Filaments of myosin tugging on filaments of actin shorten, or contract, the muscle – but the power doesn’t just come from what’s happening straight up and down the length of the muscle, as has been assumed for 50 years.

Pictured: C. David Williams with X-ray diffraction apparatus used to measure lattice spacing of filaments in moth wing muscle samples.

More people are running, biking, and exercising in other ways in hundreds of US counties, according to new research from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington.

“Around the country, you can see huge increases in the percentage of people becoming physically active, which research tells us is certain to have health benefits,” said IHME Director Dr. Christopher Murray.

UW engineers found in a recent study that the user’s experience could be key to creating an authentication system that doesn’t rely on passwords.

“How humans interact with biometric devices is critically important for their future success,” said lead researcher Cecilia Aragon, a UW associate professor of human centered design and engineering.

A new analysis of an eruption sequence at Alaska’s Redoubt Volcano in March 2009 shows that the harmonic tremor glided to substantially higher frequencies and then stopped abruptly just before six of the eruptions, five of them coming in succession.

“The frequency of this tremor is unusually high for a volcano, and it’s not easily explained by many of the accepted theories,” said Alicia Hotovec-Ellis, a UW doctoral student in Earth and space sciences.

The six-week Southeast Atmosphere Study includes scientists from more than 30 different institutions. Together they are studying how pollutants combine with natural vegetation emissions to affect climate and air quality.